In the general case of a fluid flowing through a pipe, its steadystate parameters are the flow rate and its static pressure along the length of the pipe. While the frequency was held constant throughout i. The pulsating viscous flow superposed on the steady laminar. Flow induced vibration analysis of supported pipes conveying pulsating fluid using precise integration method long liu1 and fuzhen xuan2 1 logistics engineering college, shanghai maritime university, shanghai 206, china 2 school of mechanical and power engineering, east china university of science and technology, shanghai 200237, china. In the 1920s a gentleman called john lawrence hodgson working for george kent ltd identified that pulsations induced in fluid flow caused serious reading errors with differential pressure meters. Sep 29, 2006 the fluid shear stress over each cellcovered slide was applied using a computercontrolled micro annular gear pump hnp mikrosysteme gmbh, parchim, germany. In the present analysis, the influence of thermal radiation, chemical reaction and thermaldiffusion on hydromagnetic pulsating flow of casson fluid in a porous channel is investigated.
Nonlinear hydrodynamic instability and turbulence in. However, very often flow the fluid or gas flowing through the pipeline system at working pumps and compressor stations, become unsteady. Most measurements were made at a mean reynolds number of 4000, but the. Numerical modeling of multiturn closedloop pulsating heat pipe clphp is presented in this paper for ethanol as a working fluid. A distinction must be made between the fluctuating parameters and the steadystate parameters. Flowinduced vibration analysis of supported pipes conveying. Experimental investigation on pulsating flow in a bend. Instabilities in pulsating pipe flow of shearthinning and. Based on the theory, the flow pipes conveying fluids are an important research subject of. Moreover, the velocity of pulsating fluid is assumed to be harmonically fluctuating, and has the following form. Pulsating fluid flow stimulates prostaglandin release and inducible prostaglandin gh synthase mrna expression in primary mouse bone cells. Prediction of drag reduction effect of pulsating control in. Surprisingly, even for the generic case of flow through a straight pipe, there is little consensus regarding the influence of pulsation on the transition threshold to turbulence. The numerical results obtained by integrating the momentum equations have been compared first with the analytical solution available for the newtonian fluid 29.
Pulsafeeders pulsation dampeners improve pump system efficiency by removing pulsating flows from positive displacement pumps, insuring a smooth and continuous fluid flow and metering accuracy, eliminating pipe vibration and protecting gaskets and seals. Pdf method for measuring the pulsating flow of liquids and gases. A cscfv is a tool that selectively controls the injection of water into a particular zone at a specific flow rate. Pdf vibrations analysis of pipe convoying pulsating fluid flow. N2 turbulent and laminar pulsating flows in a straight smooth pipe are compared at identical frequencies and reynolds numbers. Selective control flow valves improve the sweep efficiency by balancing the fluid flow at the upstream point, increasing oil recovery by 2%, and helping to reduce the water cut by approximately 20% abllah, maulut, and loong 2011.
The lacunocanalicular system of bone consists of osteocytes residing in lacunae and sending off processes through canaliculi, thus enabling osteocyte contact. Department of mechanical engineering, amity university uttar pradesh, sector 125, noida 20, india. An exact solution of pulsating laminar flow superposed on the steady motion in a circular pipe is presented under the assumption of parallel flow to the axis of pipe. This fluctuating flow velocity appears as parametric excitation term in the equation of motion and may. The assumption of unsteady flow imposes the condition that the pressure and flow velocity vary along the pipe. The pulsating viscous flow superposed on the steady. This confirms that the prescribed flow is realized in the test bend and also that a sinusoidal flow rate that can be expressed in the form of eq. In contrast to the criterion of pressure pulsation as specified in api 618 for pipe systems in relation to pulsation forces, the flow or velocity pulsation.
Systematic errors caused by a pulsating flow can be positive or negative and are in general related to flow or velocity pulsation amplitude and frequency. Pdf pulsating flow of casson fluid in a porous channel with. Fluid flows in nature and applications are frequently subject to periodic velocity modulations. May 26, 2020 to determine the effect of flow pulsation on the puff transition threshold, we measured the puff survival rate for varying pulsation amplitude. The governing flow equations are solved analytically by employing the perturbation technique. The evaporator temperature is set in the range of 85115 k. Mitigating the effects of pulsating flow in flow measurement. The effect of rheological parameters of the pipeline material, flow rate and base parameters on the vibration of a viscoelastic pipeline conveying pulsating fluid is analyzed.
The volume of fluid vof model is used to simulate twophase liquidvapor flow in a cphp. Semeins1, jenneke kleinnulend1 1dept oral cell biology, actavrije universiteit and universiteit van. Pulsation is a periodic fluctuation in local pressure and velocity that occurs throughout a piping system or network. Vibrations analysis of pipe convoying pulsating fluid flow. Pulsating laminar pipe flows with sinusoidal mass flux variations. The obtained calculation results with the flow pattern visualization make it possible to identify the flow features at given pulsations in the channel with respect to the.
Dealing with pulsating flow has been an issue in flow measurement for over 100 years. The effect of pulsation frequency on transition in pulsatile pipe flow. We examined the effects of 1 h pulsating fluid flow pff. Flow rates are up to about 200 gs and pulsation frequencies from 0 hz i.
A highspeed camera is used to record the twophase flow in the fpphp. Therefore, with a pulsating flow scenario the sampling rate of the electronic flow meter needs to be at least double the hz rate of the pulsations themselves. Periodontal ligament and gingival fibroblasts were subjected to a pulsating fluid flow 0. Response of periodontal ligament fibroblasts and gingival. Total mass of flow on time average is found to be identified with that given byhagenpoiseuilles low calculated on the steady component of pressure gradient. Karkenahalli srinivas computational fluid dynamics 4. The flow pulsation was generated by giving periodical acceleration and deceleration by a centrifugal pump in a closed circulation system.
The degree of pulsation in them is usually designated by frequency in hertz and a pressure amplitude see figure 1. Paper open access flow and heat transfer of fluid in a. Fluid dynamics research pulsating laminar pipe flows with sinusoidal mass flux variations to cite this article. The working fluid was water at a constant temperature of 20 c. Pdf pulsating flow of casson fluid in a porous channel. The phase lag of velocity variation from that of pressure gradient. Jan 29, 2021 in this paper, the visualization of the thermohydrodynamic behavior in flatplate pulsating heat pipe fpphp with hfe347 is experimentally investigated.
The fpphp is vertically placed with filling rate of 20% to 70% and heating power of 20 w to 140 w. Cooling of electronic components are preferred heat pipes imbedded in heat sink because of high heat transfer. Toshio nakayama sample cfd results university of sydney tohoku university contact. First, an automatic measurement system was constructed and drag reduction effect was evaluated by an experiment with various pulsation waveforms. A pulse dampener can be made in all tubing sizes using a retaining vessel and appropriately sized fittings. Flow and heat transfer of fluid in a pulsating heat pipe. Four flow pattern types and four flow directions are observed. The flow behavior is governed mostly by the ratio of viscous forces to the inertial forces in the flow. Pulsating spiral poiseuille flow journal of fluid mechanics.
Pulsating flow in a pipe journal of fluid mechanics. Numerical investigation of heat transfer of laminar and. Pulsating fluid flow modulates gene expression of proteins. Pdf flowinduced vibration analysis of supported pipes. Modeling for fluid flow and heat transfer in closed loop. Prediction of drag reduction effect of pulsating control. Flow of cerebrospinal fluid is driven by arterial pulsations. Pulsating flow of an ostwaldde waele fluid between. Pulsating fluid flow stimulates prostaglandin release and.
The performance of these meters were evaluated at both steady and pulsating conditions. The cardiovascular system of chordate animals is a very good example where pulsatile flow is found, but pulsatile flow is also observed in engines and hydraulic systems, as a result of rotating mechanisms pumping the fluid. The effect of pulsating flow on flow measurement accuracy. This is not likely the case, however, for pulsating fluid flow. If the pulsation rate is not taken into account, aliasing of the flow signal will be seen, resulting in erroneous measurement from the flowmeter. Kleinnulend j1, burger eh, semeins cm, raisz lg, pilbeam cc. Visualization of thermohydrodynamic behavior in flatplate. Osteocytes subjected to pulsating fluid flow regulate. The test bend was made from accurately machined transparent acrylic plates. The calculated and prescribed flow rates are in good agreement. After fluid flow the cells were cultured for another 60 min without mechanical stress. Pulsation unlike surge, pulsation is the rapid uncontrolled acceleration and decelera tion of units of energy. Numerical study of liquid nitrogen based pulsating heat pipe.
Computational fluid dynamic simulations of pulsatile flow in. Sep 29, 2006 osteocytes subjected to pulsating fluid flow regulate osteoblast proliferation and differentiation. Special pericellular fluid bathes the osteocyte, so a. Turbulent and laminar pulsating flows in a straight smooth pipe are compared at identical frequencies and reynolds numbers. Studies of transient and pulsating flows with application to. The fluid is injected from the lower wall and sucked out from the upper wall with the same velocity. Due to the physics of inviscid fluid flow through a conduit i. The momentum equation, governing the transient, fullydeveloped pulsating flow of an incompressible fluid through a circular duct has been considered. The considered frequency range of the flow pulsations in the channel is from 0 up to 100 hz. Nandi and chattopadhyay 26 carried out a numerical study to investigate simultaneously developing laminar fluid flow and heat transfer inside a twodimensional wavy wall microchannel under pulsating inlet flow condition. Separating oscillating and pulsating flows in an internal adverse pressure gradient geom etry are. The pulsatile, incompressible, newtonian pipe flow is one of the most studied problems in fluid mechanics over the past few decades. Xuan, journalmathematical problems in engineering, year2010. Pdf turbulent and laminar pulsating flows in a straight smooth pipe are compared at identical.
Pulsating flow in a pipe journal of fluid mechanics cambridge core. Numerical study of liquid nitrogen based pulsating heat. As the pulsating flow enters the dampener, the air pocket trapped above the fluid can absorb up to 90% of pulsation. The governing equations of motion for a pipe conveying fluid were solved using bvp4c in matlab software. In the context of this article, these units of uncontrolled energy are actually slugs of liquid mov ing through a pipe. Gene expression of proteins related to the wnt canonical pathway wnt3, lrp5, lrp6. Whether pulsatile flows are laminar or turbulent is relevant to. Pulsating fluid flow modulates gene expression of proteins involved in wnt signaling pathways in osteocytes ana santos,1 astrid d. Visualization of thermohydrodynamic behavior in flat.
Pipe flow h huininkstimulated bioluminescence by fluid shear stress associated with pipe flow. Spe169544ms an effective accelerated pulsing injection. Pulsating laminar pipe flows with sinusoidal mass flux. Numerical investigation of twophase laminar pulsating. Modeling is carried out for 1mm and 2mm id php for different numbers of turns, different orientations, and at constant wall temperature boundary conditions. Simple calculation of the velocity profiles for pulsatile flow in a blood. Womersley 19071958 in his work with blood flow in arteries.
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